How many languages are there today?

Genesis

Currently there are over 6,900 languages in the world.  Linguists have estimated that these have all derived from about 100 original language families, although others say that there were only a few original languages.  At the time of the dispersal at Babel, everybody’s language was suddenly changed, and they abandoned the area and spread across the world.  It is not known how God changed their language—the Bible is not clear on this except to say that God did it. 

Source: Answers in Genesis

At the time of the dispersal, Noah’s three sons—Shem, Ham, and Japeth—had fathered (and grandfathered) a total of 70 children, and each of these are believed to have been affected with different languages.  Some say only Noah’s 16 grandchildren were affected by the different languages, and the languages we have today are derived from those original 16.  It is interesting to see how languages are similar in how they are written and spoken, such as the commonalities found in English, French, Spanish, and Italian.  Another example are the middle-eastern languages which have similar characters and read from right to left, instead of the left to right direction that westerners are used to.